PHILADELPHIA — There is zero chance of Heat guard Tyler Johnson missing tonight’s Game 5 against the 76ers.

“He’s ready to go,” coach Erik Spoelstra said at shootaround. “He would probably punch me in the face if I said anything otherwise.”

Johnson has been gutting out an injured thumb on his shooting hand since Philadelphia center Joel Embiid knocked him to the floor on a screen in Game 3. He’s been practicing and playing with tape holding it in place, and it’s definitely hampered him.

He feels it every time he handles the ball, even in something as mundane as dribbling, and it’s made an already tough series even more frustrating for him. Johnson, who spends every bit of energy he has trying to defend 76ers guard J.J. Redick as he runs around screens all night, has averaged six points and shot 7 of 15.

In Game 4, a loss that put the Heat down 3-1 and has them facing elimination tonight at Wells Fargo Center, he went 0 for 1 and had two fouls in just 13 minutes of action.

Those aren’t viable numbers for a starting shooting guard, and they’re a big dropoff from what Johnson did in the regular season while averaging 11.7 points, 3.4 rebounds and 2.3 assists per game. Spoelstra spoke with him over the last few days about how get rolling again, but that’s going to be a challenge.

“I want to be as involved as I can, but it’s because I know I can help,” he said. “It’s not because I feel like I need X amount of shots. It’s coming from a place of I feel like I can contribute to the team. We were talking about it and trying to figure out ways in which I can be effective, not just for myself but for the team.”

It’s particularly bad timing for Miami as it manages a shoulder injury to fellow starter Josh Richardson. He sprained the A/C joint in his left shoulder (he’s a right-handed shooter) in the last game, and his status is uncertain for tonight.

While Richardson will probably end up playing, he won’t be at full strength. That could mean more minutes for Rodney McGruder and other reserves.

Johnson has been a factor defensively, but not enough to get him on the floor when the game’s on the line. Spoelstra played him for three minutes in the fourth quarter of Game 1, and he has not appeared since.

The Heat still trust him, though, and Johnson’s teammates have been impressed by how he’s fought through the issue.

“When he’s healthy, he gives us a lot,” point guard Goran Dragic said. “He gives us good defense and attacks the paint really well.

“But you can see why we love Tyler. Some players, with that kind of injury, they would already be done for the season, but he’s still here with us. He’s out there competing, giving us everything he’s got. That’s why I appreciate him so much.”

Dwyane Wade is optimistic that playing hurt will force Johnson to be sharper and more attentive, especially when he’s guarding Redick.

That would be big for the Heat considering he’s averaging 18.3 points per game and shooting 45.3 percent from the field in the series. He hit them with 28 points in the opener and 24 on Saturday.

“When you have some form of injury, it makes you focus in on your job a little bit more,” Wade said. “He can’t be late on a screen because if he’s late, they’re gonna screen him and hit him hard, and it may hurt him. He needs to be there early, be ahead of things.”